If the singular form of the noun does not end in s or an s sound, add the apostrophe and s (’s).

Singular

Singular Possessive

• teacher

teacher’s

• cousin

cousin’s

• cat

cat’s

If the singular ends in s or an s sound, add the apostrophe (’ ) or the apostrophe and s (’s) if the additional s sound is desired.

Singular

Singular Possessive

• glass

glass’ or glass’s

• bus

bus’ or bus’s

• fox

fox’ or fox’s

If the plural form of the noun does not end in s, add the apostrophe and s (’s).

Plural

Plural Possessive

• women

women’s

• people

people’s

• alumni

alumni’s

If the plural form of the noun ends in s, add only the apostrophe (’ ).

Plural

Plural Possessive

• computers

computers’

• diskettes

diskettes’

• modems

modems’

The possessives of proper nouns are formed in the same way as the possessives of common nouns. If the singular form of the name does not end in s, add the apostrophe and s (’s). If the singular ends in s or an s sound, add the apostrophe (’ ) or the apostrophe and s (’s). The plural possessive always is formed by adding the apostrophe to the plural form.

ProperNoun

SingularPossessive

Plural

PluralPossessive

• Phil

Phil’s

Phils

Phils’

• Ellis

Ellis’ or Ellis’s

Ellises

Ellises’

• Jones

Jones’ or Jones’s

Joneses

Joneses’

• Romero

Romero’s

Romeros

Romeros’

Certain expressions relating to time, distance, and value also are written with an apostrophe.

• a moment’s reflection

• four months’ wages

• one kilometer’s length

• seven miles’ jog

• a dollar’s cost

• two cents’ worth

The singular possessive and the plural possessive of compound nouns are formed by adding the apostrophe to the end of the compound word.

Singular Possessive

Plural Possessive

• sister-in-law’s

sisters-in-law’s

• son-in-law’s

sons-in-law’s

Joint ownership is shown by making the last word in the series possessive. Individual ownership is shown by making both parts possessive.

• The party was at Mitch and Dave’s place. (joint ownership)
• I programmed Cheryl’s and Deborah’s computers. (individual ownership)

Use an apostrophe in indefinite pronouns to show possession. The possessive case of indefinite pronouns is formed in the same way as the possessive case of nouns.

• somebody’s coat

• everyone’s responsibility

• one’s integrity

• others’ paperwork

When showing the possessive of the personal pronoun it, no apostrophe is used. An apostrophe and s (’s) is used after it to indicate “it is.”

• I put the book in its place on the shelf. (indicates possessive of it)
• Those black clouds make me think it’s going to rain. (indicates it is)

Use the apostrophe with s to form the plural of numbers, letters, signs, and symbols.

• Carolyn has scored 100’s on all her math tests.
• Your written “o’s” look more like “a’s.”
• In Dar’s report, he used “$’s” to indicate money.
• Don’t forget to include “@’s” in all email addresses.

In a context in which the plural is clear, apostrophes after upper-case letters are not necessary.

• Condi got four As, two Bs, and three Cs.

It is not necessary to use an apostrophe to create the plurals of years, decades, or abbreviations.

• Most of the scientific discoveries in that area were in the 1990s.
• All the PhDs in the department received a raise.
• Sometimes I wonder about the IQs of such gullible people.

Use the apostrophe to indicate the omission of a word, letters, or numerals.